Description of the problem:

When webstorage ( tomcat@thermostat service) is stared, tomcat generates SecureRandom. OpenJDK by default uses /dev/random for that, which is blocking. As a consequence loading of thermostat webstorage can take very long time on systems with entropy shortage (such as VMs). 

I experienced this problem when testing on beaker machines, where generating of SecureRandom often takes 100s of seconds. 


From /var/log/tomcat/thermostat-web-storage.*.log:

Apr 20, 2016 8:55:26 AM org.apache.catalina.util.SessionIdGenerator createSecureRandom
INFO: Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [491,578] milliseconds.
INFO - WebStorageEndPoint: Initializing web service
FINEST - WebStorageEndPoint: THERMOSTAT_HOME == /opt/rh/thermostat1/root/usr/share/thermostat
...

In log above you can see it took 491,578 ms (> 8min) . Usually I get about 200,000 ms.

system used was rhel7

with following java -version 
openjdk version "1.8.0_65"
OpenJDK Runtime Environment (build 1.8.0_65-b17)
OpenJDK 64-Bit Server VM (build 25.65-b01, mixed mode)


As you know I have already experienced this issue in the past with thermostatQA (in VM, with external tomcat) , where I workarounded issue by using /dev/urandom instead of /dev/random. It reduces time needed to generate SecureRandom to less than 1s.


Possible Solution:

You could consider adding following parameter to JAVA_OPTS in /etc/sysconfig/tomcat@thermostat to use /dev/urandom instead of /dev/random :
-Djava.security.egd=file:/dev/./urandom
( /./ is intentional [1] [2] )

 
Resources
[1] http://stackoverflow.com/questions/137212/how-to-solve-performance-problem-with-java-securerandom
[2] https://bugs.openjdk.java.net/browse/JDK-6202721